Tease-proof snap-action switch



Sept. 5, 1961 c. A. BALL, JR

TEASE-PROOF SNAP-ACTION SWITCH Filed 001;. 19, 1959 35 W/ZB gs 2 12 15 13 A7)? L w 1 R H m NE. K MA 0 ms N z A 4 a M w 0 United States Patent 2,999,138 TEASE-PROOF SNAP-ACTION SWITCH Charles A. Ball, Jr., Highland Park, Ill., assignor to Cherry Electrical Products Corp., Highland Park, 111., a corporation of Illinois Filed Oct. 19, 1959, Ser. No. 847,204 '1 Claim. (Cl. 200-67) My invention relates to a new and useful improvement in a tease-proof snap-action switch and more particularly to an electrical switch having a flexible contact blade movable between fixed contact bearing terminals.

An object of my invention is in the provision in a switch of this character of a movable switch blade that is caused to move with a snap-action only upon full actuation of an actuator member. The construction .and arrangement of par-ts prevents the movable switch blade to move due to jarring or improper function of the switch actuator.

Another object of my invention is in the provision in a switch of this character of an arrangement of parts whereby the contact pressure between the movable contact and a fixed contact is increased prior to the snap action movement of the movable switch blade. v

A further object of my invention is in the provision in a switch of this character of a flexible contact blade which in its normal assembled position resembles an extended wave, which wave is responsible for the contact pressure between contacts and the snap-action movement of the blade when the natural wave thereof is distorted by a suitable actuator.

Other objects will appear hereinafter.

The invention consists in the novel combination and arrangement of parts to be hereinafter described and claimed.

The invention will be best understood by reference to the accompanying drawings showing the preferred form of construction and in which:

FIG. 1 is an elevational view of my improved teaseproof snap-action switch;

FIG. 2 is a side elevational view of my switch showing a section thereof removed;

FIG. 3 is an elevational view similar to FIG. 2 but showing the parts in actuated position; and

FIG. 4 is a perspective view of my flexible contact blade in its natural unmounted condition.

Referring to FIG. 1 I show a housing for my improved switch. This housing 10 comprises complementary sections adapted to be mounted together in facial relationship by means of rivets 11 or the like.

As each of the sections of the housing 10 are identical I will show and will describe but one. Referring to FIGS. 2 and 3 which show an elevational view of one of the sections it is seen that the sections are provided with a plurality of cavities 12, 13 and 14. The cavity '12 is defined by a rear wall 14' and oppositely disposed triangularly shaped projections 15 and 16. The rear cavity 13 is defined by the projections 15 and 16 at one side and similar oppositely extending triangularl'y shaped projections 17 and 18 at the other side. The cavity 14 is defined at one side by the projections 17 and 18 and at the other side by the end wall 19.

A pair of spaced apart contact bearing terminals 20 and 21 are adapted to have one end portion thereof projected out of the end wall 14' and having their opposite contact bearing ends disposed within the cavity 12 as seen in FIGS. 2 and 3. The end wall 14' is provided with a V-notch 22 formed therein with the notch 22 spaced equally from the terminals 20 and 21 and facing inwardly of the cavity 12. The opposite end wall 19 is provided with a like V-notch 23. It should be noted that the V- notch 22 as well as the v-notch Z3 lies in a horizontal plane which extends through the restricted openings between the oppositely extending triangularly shapedprojectors 15, 16 and 17, 18.

A flexible switch blade 24 is shown in FIG. 4 in its natural unmounted condition. One end 25 of the switch blade 24 has the width thereof reduced so as to provide shoulders 26 and 27. The flexible switch blade 24 between the shoulders 26 and 27 and the opposite end 28 thereof is of a longitudinal length greater than the distancebetween the V-notches 22 and 23 formed in the respective end walls 14 and 19. Because of the greater length of the switch blade 24 when the same is mounted in the housing 10 it must be placed in a waved condition as shown in FIGS. 2 and 3. In such waved condition the blade is formed so that it disposes a peak of such Wave in each of the cavities. Referring to FIG. 2 it is seen that the peak 29 is disposed in the cavity 12 and that the oppositely extending peak 30 is disposed in the cavity 13 while the peak 31 which extends in the same direction as peak 29 is disposed in the cavity 14.

The end 28 of the switch blade 24 is seated in the V-notch 22 while the shoulders 26 and 27 are seated in the V-notch 23. By such an arrangement I have imposed end pressure upon the medial portion of the switch blade 24 so that it will assume the wave condition as hereinbefore described.

Formed in the housing 10 is a passage 32 which has open communication with an enlarged recess 33 formed in the top wall of the cavity 14. An actuator 34 is positioned within this passage 32 and is adapted to be reciprocated therethrough. This actuator 34 terminates inwardly into an enlarged head 35 which is adapted to sit in the recess 33 formed in the top wall of the cavity 14. This enlarged head 35 is provided with a nipple 36 which is adapted to engage the highest elevational point of the peak 31 disposed in the cavity 14.

In order to maintain the flexible contact 24 in its mounted waved condition I provide a coil spring 37. This coil spring 37 sits in a recess 38 formed in the bottom wall of the cavity 14. The spring 37 as well as the point of contact of the nipple 36 of the actuator 34 is in vertical alignment through a centerline that extends through the highest elevational point of the peak 31 as seen in FIG. 2.

In actuating my improved tease-proof snap-action switch the actuator 34 is depressed so that the peak 31 of the flexible contact blade 24 is depressed downwardly against the action of the spring 37. This movement of the actuator 34 deforms the peak 31 within the cavity 14. When the peak 31 is indented so that such indentation extendsbelow the longitudinal centerline that extends between the notches 22 and 23, the flexible switch blade 24 by reasonof the end pressure imposed on the blade 24 will cause a reversing of the peaks 29 and 30 of the waved blade 24 into the positions shown in FIG. 3.

By the flexing of the restricted wave of the blade 24 so that the peaks thereof are forced to reverse their position through a longitudinal plane, a snap-action movement results in the peak 29. By such snap-action the contact 39 carried by the peak 29 is moved out of engagement with the contact 40 carried by the terminal 20 and into engagement with the contact 41 carried by the terminal 21. However, it should be noted that because the blade 24 is disposed within the housing 10 in a continuous waved condition that has three peaks thereof before the peak 29 is caused to reverse its position within the cavity 12 the peak 31 must be completely deformed by the actuator 34 and the kinematic motion created thereby transmitted to the peak 30 causing it to reverse its condition and passing such kinematic motion into the peak 29.

It should be noted that the blade 24 in its waved condition possesses sufficient end forces to produce a desired contact pressure between the contact 39 and the contact 40. When the kinematic motion is commensed through the peaks of the blade 24 the contact pressure above mentioned is increased until the snap-action movement takes place as hereinbefore described.

When the actuating pressure is removed from the actuator 34 the compressed spring 37 causes a reverse action and returns the blade 24 to the condition as seen in FIG. 2.

The structural embodiment above defined constitutes an improvement over the snap-action switch shown and described in my copending application Serial No. 847,205.

While I have illustrated and described the preferred form of construction for carrying my invention into effect, this is capable of variation and modification without departing from the spirit of the invention. I, therefore, do not wish to be limited to the precise details of construction set forth, but desire to avail myself of such variations and modifications as come within the scope of the appended claim.

Having thus described my invention, what I claim as new and desire to protect by Letters Patent is:

A tease-proof snap-action switch comprising identical sections adapted for facial abutment with respect to each other to provide a housing and having transversely extending projections spaced from each other to provide an intermediate cavity and end cavities on opposite sides of the intermediate cavity, each projection being divided into an upper and lower section with each section formed substantially triangularly in crosssection and having their apexes disposed on a longitudinal line through the housing, the end walls of said housing having internal seats formed therein in line with said apexes, a flexible switch blade within said housing and extending between the apexes of said sections with opposite end portions seated in said seats, the length of said blade being greater than the distance between said seats whereby when said blade has its opposite ends seated in said seats the blade will be undulated to provide alternate bowed portions located in said cavities, one end portion of said blade having a terminal extending from the housing, parallelly extending terminal plates in the opposite end of the housing and extending exteriorly thereof and having confronting contact heads located within the end cavity adjacent said end wall, and means for flexing successively the bows of said blade from the said one end of the housing in a direction toward said opposite end of said housing to bring the bowed portion of the blade in said adjacent cavity into alternate contact with said contacts of said terminals, said means including an actuator carried by the housing and engaging the bow of the switch blade within the cavity adjacent the other end wall of the housing.

References Cited in the file of this patent UNITED STATES PATENTS 1,939,286 Spencer Dec. 12, 1933 2,374,435 Jordan Apr. 24, 1945 2,395,698 Tiffany Feb. 26, 1946 2,414,778 Tratsch Jan. 21, 1947 2,444,529 Puster July 6, 1948 FOREIGN PATENTS 485,955 Italy Oct. 22, 1953 

